1. Field of the Invention
The present invention relates generally to medical mesh implants conventionally used for tissue support and cell growth latices. More specifically, the device relates to a woven or warp knitted mesh implant device, having a bonding of titanium positioned to cover and provide an interface to the exposed fiber surfaces and contacting body tissue. So positioned, the titanium provides significantly enhanced bio-compatibility of the underlying fabric and device with the body in which it implants. The device is especially well adapted for employment in breast reconstructive surgery through the provisions of thread weaving, or especially knitting configurations, which provide a customized implant support structure in combination with bio-compatibility.
2. Prior Art
Breast cancer is one of the most common cancers among women. If the disease is not caught early, it is common that large portions of breast tissue are removed. In a conventional procedure called mastectomy, one or both breasts are partially or completely removed in order to treat or subsequently prevent breast cancer. Since such procedures generally result in a substantial amount of tissue being removed, many women will then opt for breast reconstructive surgery in order to reform the breast into a natural looking state. It is often acknowledged that the process of cancer treatment and removal of breast tissue can weigh heavily not only on the patients physical but also emotional well being. Thus, such surgery to reconstruct the breast can allow the patient to maintain self confidence after such an ordeal.
Many techniques of breast reconstruction and enhancement are known in the art. Such procedures generally involve employment of prosthetics, one's own body tissue, or a combination thereof, which are employed as implants for reforming the breast. Prosthetic implants are the most common technique known in the art and are used both for reconstructive and cosmetic surgery. This involves the employment of silicon, saline, or other suitable material formed implants, tissue expanders or the like, which are placed either below the muscle (submuscular) or above the muscle (subglandular) for forming and shaping the breast.
A first well known surgical method for breast reconstruction is transverse rectus abdominal muscle flap (or TRAM flap) surgery wherein a portion of abdominal tissue is employed to reconstruct the breast. The abdominal muscle is typically removed from the abdomen and then placed where the breast is to be formed. By employing ones own body tissue, the reconstructed site most often accepts the tissue and will limit further complication in that manner.
However, since initial removal of tissue from the abdomen is required, the procedure is time consuming, requires multiple surgeons and surgical sites, and may require long convalescence. In addition, the abdominal muscle may stay weakened and may further suffer from incisional hernias in the abdomen, thereby further prolonging recovery. Further, additional scars will typically be present and visible in the abdominal region at the site of tissue removal. As such, this type of surgery is typically considered a higher risk then prosthetic implant surgery.
Another example of body tissue breast formation is referred to as deep interior epigastric perforator (DIEP). This technique is also known to generally require multiple surgeons performing multiple incisions at different sites on the patient. In this procedure the surgeons harvest and employ abdominal tissue, however without muscle tissue, wherein only skin and blood vessels are transplanted. This method is often preferred over TRAM technique since muscle is not removed, and recovery can be shorter. However, this technique still suffers from some of the downfalls of the TRAM technique, including but not limited to, large amount of operating room and surgeon time, multiple surgeons, and surgical scars on multiple parts of the patients body.
Still another well known technique involves the transplant of skin and muscle from the back, namely the latissimus dorsi. Back muscles are generally thinner than the abdominal muscles, which allows surgeons to combine the muscle tissue with prosthetic implants such that the implant can maintain a more natural looking shape, volume, and feel. However, this technique again generally involves multiple surgeries and surgeons and is a time consuming surgery with a long post-operation recovery. Further, the removal of muscle tissue may result in the back muscle being weakened which can cause long term pain for the recovering patient. In addition, large scars will remain on the back and breast area.
While these and other techniques endeavor to minimize rejection issues by employing the patient's own body tissue for supporting existing breast tissue, or implanted prosthetics, this positive goal is generally negated by the fact that multiple surgeries and surgeons are required, and the fact that the patient has multiple incision sites and lost remote tissue that must heal and can become infected and painful. Consequently, a device and method which would provide customized support to the surgeon in their art to reshape the breast aesthetically, with minimized rejection and not requiring extra surgical procedures, would be of benefit to both patient and surgeon in such procedures.
As a conventional solution, the use of medical surgical mesh material as a support material is known in the art. One skilled in the art may immediately recognize many prior and related art provides surgical mesh devices, typically made from synthetic materials such as woven polypropylene or other synthetic and natural fabrics, which are implanted during all types of reconstructive or cosmetic surgery. Conventionally, the woven surgical mesh is provided as a flat substantially rectangular sheet which the physician must accurately cut to size in an attempt to fit the natural curvature of a breast as needed per patient for adequate support.
Unfortunately, the conventional woven mesh materials used today make no provision for accommodating stretch in one or both directions on a controlled basis. This is especially true with conventionally employed woven fabrics which generally provide no stretch or stretch in a single direction of the either the warp or the fill of the weave.
Because of this inability to customize elasticity and stretch to the mesh, these conventional devices may fail in providing adequate support and comfort in the natural movement and feel of the breast which for each human is of a custom dimension and area. This poor fit and lack of elasticity to allow for form fitting of the breast, may result in additional surgeries to correct such inconsistences. In addition, as has been discovered recently from long term implants, due to body reactions to some synthetic materials used for weaving such mesh devices, the mesh can be rejected by the patient's body even years after implantation. This rejection either evidenced immediately or over a term of years, can also be the causation of infection, damage to tissue, and again the need for subsequent surgeries to remove or replace the mesh device.
Further, currently provided to physicians for breast support are conventional square sheets of woven mesh fabric which are neither configured to size nor cut to shape to form the proper three dimensional shape when placed in a supportive engagement in an arc under the breast tissue or implants. As such, surgeons in the operating room, must take valuable time and cut the woven fabric sheet in the operating room during the procedure.
As such, this need for cutting woven mesh fabric, frequently results in uneven or miss-cut sheets of woven mesh which are then implanted and must be forcefully stretched or manipulated into a “fitted” engagement to the breast of the patient. To maintain this fitted engagement, the surgeon resorts to sutures or staples through the mesh and into surrounding tissue.
However, as noted, conventional mesh fabric being normally woven structures, are typically adapted to allow for partial stretch and only in one direction of either the warp thread running longwise or the fill thread running 90 degrees or perpendicular to the warp. Often the mesh structure will be positioned in the patient to permit stretch in the horizontal direction in an attempt to accommodate the volume of the breast, while resisting stretch in the vertical direction, in order to maintain support for breast tissue against the force of gravity on the implant or breast tissue. This results in an improper fit around the curved area of the breast tissue in the vertical direction which can be painful amongst other problems noted herein.
One skilled in the art will quickly ascertain that the dimensions and configurations of the mesh for each breast will vary widely for each instance of the procedure and the desired outcome of breast size, shape, and form. However, as a consequence of the lack of customized implant fabric sheets, which are knitted or woven and pre-cut to fit breast tissue, and the lack of predetermined stretch and support in both directions of supported breast tissue, can adversely effect the finished shape and feel of the reconstructed breast tissue. As such, patients will frequently suffer from discomfort from the material compressing the breast tissue, or from a distaste for the visual aspects of the finished surgery. Such patients will often require further surgeries to correct any inconsistences with the mesh, or such patients may just unfortunately live with the uncomfortable current state of the reconstruction as well as the now known problems with fabric mesh rejection and infection.
Such surgical mesh is also known in the art to be employed in the abdominal region to prevent incisional hernias at the sites of muscle removal, and is commonly known for employment with other types of hernia repair. Some well known problems with conventional surgical mesh devices include high overall weight and stiffness and lack of three dimensional elasticity which is inherent to the typically rectangular woven mesh sheets. Further such mesh sheets used abdominally also have been found most recently to lack biocompatibility between the synthetic materials forming the sheets and contacting surrounding body tissue, thereby causing inflamation and in some cases illness and rejection.
When such surgical mesh is employed with breast reconstructive surgery, as noted, the stiffness and weave of such conventional mesh in one or both directions, can seriously inhibit the natural look, movement, and feel of the breast tissue and such is undesirable. Further, stiff or inelastic materials formed into woven structures can prove more difficult to handle by the physician during implantation due to the need to customize the planar non elastic sheet, to fit the curved three dimensional shape of a breast. Such misfitting sheets customized in the operating room frequently require suturing or stapling to maintain their position in the body.
As also noted, bio-compatibility and the possibility of the body's rejection of a fabric implant is a continuing problem with nearly all implant devices and most recently has been shown to be a particularly acute problem with woven fabric mesh. This lack of compatibility has been shown to be caused by the material forming the threads or yarn of the woven material.
A conventional solution is the use of known synthetic materials, such as polyanhydrides, which provide some bio-compatibility, in place of the conventional polypropylene or polystyrene or polyethylene yarns and threads used in mesh weaving. These materials may be provided in continuos unitary fibers, filaments, or strands of the material, which are sewn, woven as needed, to construct the planar mesh for implantation.
However, even such conventional thought to be bio-compatible synthetics, are still known to be subject to blood clot formation, infection, allergic reactions and more, and have been shown to be never completely bio-compatible. In addition, when employing such known bio-compatible synthetic or natural materials for forming into the yarn, fine fibers or filament strands which is then woven as needed, it has been found the strands in the weave may become brittle when formed into monofilament strands, and may incur some problems with stiffness and breakage.
Therefor, there is a need for a mesh implant device, able to employ known materials suitable for construction into a planar mesh structure, such as polypropylene or polystyrene or polyethylene, which is also biocompatible. Such a device should be able to employ conventional yarns for weaving or knitting to keep costs reasonable, but which also are provided an exterior surface layer, or coating, on the formed material or the yarn forming the material, which may then be employed for implantation and provide enhanced bio-compatibility. Thus, the provision of a bio-compatible surface layer or coating provided on the known textile yarns and strands suitable form forming into a mesh structure, should yield a finished mesh device which is adequately flexible and employs features of bio-compatibility.
Additionally, rather than forming the mesh using fabric weaving construction of warp and fill yarns or threads, which provide little elasticity except in directions normal to the two woven threads, the forming of implant fabric will be enhanced if knitted from the threads or yarns by the provision of two enhancements to implantation.
First, by knitting the mesh fabric, a three dimensional stretching may be provided which will better accommodate the vertical and horizontal curves of breast material, and provide support for the underlying breast by the elasticity yielded in three directions, knitted fabric mesh can yield. Secondly, warp knit fabric will not unravel when cut in the operating room by the surgeon as will woven mesh. Knitting machines and their function and the intertwined material yielded therefrom which won't run or ravel when cut, such as warp knit and stitches affecting the shape and elasticity such as knit, purl, cast on, cast off are well known in the art, as are weaving machines which employ warp and fill fibers to form material, and such need not be overly described herein.
This ability not to easily unravel is a particular improvement over the currently employed conventional woven mesh fabric, which even if heated to help maintain thread engagement, will unravel along unfinished edges when cut, and even when not cut. If this woven fabric is cut on a diagonal line to the perpendicular woven threads, unraveling is particularly acute, and the fabric on the diagonal will over stretch under tugging force. This unraveling and over stretching is a nightmare for a surgeon customizing a planar woven sheet the operating room which is remedied by the use of knitted fabric herein described as a particularly preferred mode of the device.
With regard to biocompatibility the mesh material herein is mated with a layer of titanium. Titanium further has the inherent property to osseointegrate, wherein there is direct structural and functional connection between living bone and the surface of the titanium making it further desirous for medical use in implants and the like. Titanium is additionally non-ferromagnetic, making it less likely to interfere with imaging during subsequent conventional MRI technology when combined with the underlying thread or yarn of the knitted mesh.
However, in most cases, titanium coatings or layers must be deposited for adherence at high temperatures which would melt the underlying synthetic fabric yarn forming the mesh scrim provided by such materials for example, polypropylene or polyethylene or other woven or knitted polymeric fabric formed to thread or yarn to be suitable for use in knitting or weaving a mesh structure.
As such, there is a continuing unmet need for an improved medical mesh implant material especially for use to support non planar body tissue having three dimensional curves such as the breast. Such a material should provide enhanced bio-compatibility with surrounding body tissue, to alleviate the infection and rejection problems of current implant fabrics through the provision of a titanium layer on the surface of the material which contacts the patient's flesh.
However, the placement of the metallic titanium coating on the contact surface of the thread or yarn forming the knitted or woven mesh should be engaged in a fashion so as to not melt, or to stiffen the supple nature of the underlying woven or knitted polymeric yarn or thread material. Further, such an implantable fabric should be formed in a manner to provide the surgeon with predictable support, as well as predictable elasticity of the formed mesh sheet, even when employed in a curved surface, through weaving or most preferably knitting the initially planar mesh in a manner that provides vertical support to hold the tissue or implant and thereby resist sagging, but, allow lateral and diagonal elasticity to accommodate the curved and arched nature of the formed breast and thereby provide a more natural appearance and movement such as while walking, to the patient's breasts once implanted.
Further, such a mesh fabric should be providable in a kit of a plurality of individual mesh pieces, each of varying sizes of mesh swatches, which can either be employed as-is due to the chosen customized size, or cut to dimensions for easy implantation with little or no trimming and without unraveling once so cut. Finally, such an implantable mesh should ideally provide a visual aid, which when viewed by a user such as a physician, to cut the implant mesh along predictable lines should it need it, to form the desired dimensions, which allow a surgeon to obtain an even arc or curve of the fabric engaged with a breast, once cut, but to concurrently limit folding and kinking and unraveling and thereby provide the most correct fit for a patient as needed.
The forgoing examples of related art and limitation related therewith are intended to be illustrative and not exclusive, and they do not imply any limitations on the invention described and claimed herein. Various limitations of the related art will become apparent to those skilled in the art upon a reading and understanding of the specification below and the accompanying drawings.